Technical description and composition of the DEXP H28D7300K TV, panel type and applicable modules. The composition of the modules.DEXP LED
Model: H28D7300K
Chassis / Version: TP.MS3463S.PB801
Panel: HV280WX2-260
T-CON: HV280WX2-260_X-PCB 47 47-6001127
LED driver (backlight): integrated into MainBoard
PWM LED driver: SN51DP
MOSFET LED driver: PA110BDA
Power Supply (PSU): integrated into MainBoard
PWM Power: PWM SOT23-6
MainBoard: TP.MS3463S.PB801_H28D7300K
IC MainBoard: CPU: MSD3463GU, SPI Flash: 25Q64, AUDIO: OB6220VP
Tuner: XF-3SDT-H
Technical Specifications H28D7300K
DEXP H28D7300K
General repair guidelines for TV LCD LED
Possible malfunctions
- The DEXP H28D7300K TV does not turn on at all. There is no reaction to the remote control and control buttons from the front panel. Indicator lights do not light or flash.
In such cases, the AC / DC voltage converter, which is combined with the main board TP.MS3463S.PB801, is often faulty. It is necessary to measure the output voltages in its secondary circuits, and if they are completely absent, it is necessary to check the serviceability of power switches and rectifier diodes for possible breakdown (short circuit).
In case of any breakdowns in the secondary circuits, the converter can operate in emergency short circuit mode, and during short circuit in the power elements of the primary circuit, the mains fuse or the current sensor at the source of the key more often breaks.
Mos-Fet keys used in switching power supplies usually fail due to a malfunction of other elements that can put it out of operation in key mode or provoke an excess of the maximum current or voltage. These can be circuits supplying the PWM controller, damping or frequency-setting circuits, or elements of OOS (negative feedback) in the stabilization circuit. PWM controllers (PWM) PWM SOT23-6, in the absence of external damage and short circuit between the terminals, are checked by replacing with obviously good ones.
- There is no image, there is sound, it responds to the remote control, the channels are switched. In some cases, the image appears when you turn on and immediately disappears.
Often in such cases, there is no LED backlight. The reason for this may be a break in the LED circuit, or a problem in stabilizing their power supply.
It is impossible to check the LED line for breaks without disassembling the panel with a multimeter or tester. For these purposes, it is necessary to open all series-connected PN junctions and a voltage of the order of tens of volts will be required, and ideally, a current source. Having disassembled the panel, it is necessary to check each LED separately. Chinese multimeters, as a rule, light up a single 3-volt LED in the forward direction. In the case of using dual 6-volt LEDs, the PN junction of its protective zener diode can serve as a health indicator. In faulty LEDs, the zener diode will either be cut off or broken into short-circuit.
- The indicator on the front panel blinks, the TV does not turn on in the operating mode, it does not respond to the remote control.
Repair or diagnostics of the TP.MS3463S.PB801 motherboard should begin by checking the stabilizers and power converters needed to power the chips and matrix. If necessary, update or replace the software (software). In cases of complex repairs of MB (SSB) and in the presence of the necessary skills and equipment, sometimes it may be necessary to replace its CPU chips: MSD3463GU, SPI Flash: 25Q64, AUDIO: OB6220VP and other possible faulty components. Malfunctions associated with the application of BGA soldering technologies are usually easily diagnosed by the heating method.
If you suspect a malfunction of the XF-3SDT-H tuner, first of all, you need to verify the correctness of the software, as well as the presence of the necessary voltage levels and pulses of data exchange with the processor via the I2C bus at the corresponding terminals of the tuner.
Attention to users! Self-repair of a DEXP H28D7300K TV without the appropriate qualifications and necessary experience can lead to its complete non-repairability!
FIRMWARE FOR SPI FLASH -----------> DEXP H28D7300K, Main: TP.MS3463S.PB801, Panel: HV280WX2-260
The appearance of MainBoard TP.MS3463S.PB801_H28D7300K is shown in the figure below:TP.MS3463S.PB801_H28D7300K
Main features of the DEXP H28D7300K device:
Installed matrix (LED-panel) HV280WX2-260.
The matrix control uses the Timing Controller (T-CON) HV280WX2-260_X-PCB.
To power the backlight LEDs, a converter is used, combined with the main board TP.MS3463S.PB801_H28D7300K, controlled by the SN51DP PWM controller. As the power elements of the LED driver, keys of the type PA110BDA are used.
The power module is combined with the MainBoard and is made according to the flyback AC / DC voltage converter circuit using PWM SOT23-6 microcircuits.
MainBoard - the main board (motherboard) is a module TP.MS3463S.PB801_H28D7300K, using CPU chips: MSD3463GU, SPI Flash: 25Q64, AUDIO: OB6220VP and others.
The XF-3SDT-H tuner allows you to receive television programs and tune to channels.
DEXP H28D7300K TV with HV280WX2-260 LCD, 28 "(71 cm) diagonal size of 16: 9 format. The required screen brightness of 180 cd / m² is provided by LED backlighting. Contrast - the ratio of maximum brightness to minimum is 1200: 1. The LCD panel uses direct pixel illumination with rear LEDs - Direct LED. You can watch broadcasts and movies and images in high quality HD at a resolution of 1366x768 pixels in the standard of graphic decomposition 720p (HD Ready). Supported media file formats: MP3, WMA, MPEG4, HEVC (H.265), MKV, JPEG.
The power of the sound system 10 W (2x5 W) provide two speakers. The audio processing system NICAM STEREO is used.
The external interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV, audio x2, component, VGA, HDMI x3, USB. An output for connecting headphones is provided. A digital tuner is capable of receiving television channels in the DVB-T MPEG4, DVB-C, DVB-T2 standards.
The power consumed by the TV working in the network mode is 70 watts.
Overall dimensions: with stand 635x421x211 mm, without stand 635x379x87 mm.
TV Weight: with stand: 3.3 kg, without stand: 3.1 kg.
Attention! The HV280WX2-260 panel of a DEXP H28D7300K LED TV is an expensive and unreliable element.
Avoid any impact on the glass and pressure on the surface of the screen to avoid damage to the LED panel!
It is also unsafe to get liquid on the screen. Sometimes one drop is enough if it flows down the glass onto the cables so that the TV becomes unrepairable.